A group of online volunteer test subjects has been helping me put a finer point on how much intensity conventional training methods deliver to a muscle group.

Personally, I love doing this stuff because it helps all of us make decisions with facts instead of with unquestioned and untested premises.

What that data showed was a bit shocking to me and I thing it might shock you as well.

The First (Very) Informal Study

A group of trainees measured the maximum weight they could statically hold on the bench press for 5 seconds. Then they selected a lighter weight and measured how long they could hold it.

As you might intuitively expect, the lighter the weight, the longer you can hold it. But the proportion is what is astounding. When the weight was reduced by 50% the amount of time they could hold it was not twice as long – it was 10.2 times longer. That is interesting on its own, but what amazed me was that when we calculated the difference in intensity (weight held per second) we found that this 50% weight reduction meant the intensity dropped to only 5.2% of maximum.

So a 50% reduction in weight means a 900% increase in hold time. Which give you a very strong clue as to how much less intensity there is when you reduce the weight.

Intensity is (Almost) Everything

We all know that if you want to get bigger, stronger muscles you have to lift weights. But why? It’s because the muscles of the human body adapt to stress - and the relevant stress for muscles is the work they are forced to do. Bend your elbow 1,000 times with no weight in your hand and your biceps doesn’t get any stronger. Bend it three times with a 90 lb dumbbell in your hand and it does get stronger.

The only difference is the intensity of the effort. The higher the intensity you force your muscles to generate, the bigger and stronger they will become. That is the entire reason that heavy gym equipment exists.

Knowing that, why lift with less intensity? Why deliberately stand in the shade when you want a darker tan?

Every exercise for every muscle group should be engineered to maximize the intensity you can generate. Using lighter weights generates disproportionately lower intensity. (Thus, a 50% reduction in weight yields 95% less intensity.)

Want More Proof?

A smaller group of nine trainees did a second (very) informal study. They performed lat pulldowns with 40% of the weight they could hold for 5 seconds. They did full range reps to failure, just like most people in the gym would do. They lifted until they could not complete another rep.

At the end of the set using 40% of their 5-second maximum weight – and so completely fatigued they could not do another full rep - they immediately doubled the weight and attempted a 5-second static hold in their strongest range of motion.

What happened when these “exhausted” muscles that had “gone to failure” tried to hoist double the weight? One hundred percent of the trainees were able to lift the increased weight. Only one of the nine subjects was not able to hit 5 seconds, the other eight achieved from 9 to 20 seconds, averaging 12.4 seconds.

That’s how bad light weights are at generating the maximum overload your muscles are capable of. One hundred percent of subjects had dormant muscle fibers that were not being taxed during reps to failure, and could therefore generate many times the intensity (measured in pounds per second) immediately after the low-intensity set.

But here is the really shocking part.

Can you see what a waste of time it is to play around with sub-maximal weights? How can you stimulate new muscle growth by taxing your muscles at 5% of their capacity? You can’t. Yet, remember, the first guys statically held that lighter weight as long as they could. Their arms were tired, their chest was tired, they couldn’t hold the weight another second . . . yet they were exercising at a measly 5.2% of their peak output.

And the second group went to “failure” using full range reps just like everyone in the gym does. And after so-called “total muscular failure” they could double the weight and do a static hold. So those full range reps obviously were not taxing all the muscle fibers, were they? Nor, obviously, were they stimulating maximum muscle fiber growth. The so-called “need” for full range is a huge lie.

I’ll say that again: the so-called “need” for full range is a huge lie.

Want Better, Faster Results?

When you use lighter than maximum weights for any exercise you cheat yourself out of progress. That is why Static Contraction Training is so effective and efficient; in uses the maximum weight you can sustain for a brief 5 seconds. The intensity has to be felt to be believed. When your muscles are forced to operate at that upper limit they adapt with urgency - like a pale Norwegian stepping into the noonday African sun. Go to the gym and try it.

One of the nice things about these measurements is you can go into your gym today and test the veracity of all the above. This is a universal phenomenon; light weights generate much less intensity. And intensity is (almost) everything when it comes to getting bigger, stronger muscles.

Want to maximize intensity? Do Static Contraction training and perform maximum holds for 5 seconds. You have to feel it to beleve it.

My thanks to the above volunteers who helped move strength training closer to a science and farther from macho gym hype.